126 research outputs found

    On the Role of Power Electronics in Visible Light Communication

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    The continuous demand of increasing data rates provided by wireless communication systems is contributing to saturating the RF spectrum. Visible Light Communication (VLC) systems aim to alleviate this congestion by using the visible light spectrum. These systems have been proposed to make use of High-Brightness LEDs (HB-LEDs) not only for lighting, but also for transmitting information by rapidly changing the intensity of the emitted light. A critical issue is that VLC requires a fast HB-LED driver in order to reproduce the target light intensity waveforms, which can include components of several MHz. Consequently, the HB-LED drivers proposed to date are based on the use of an RF Power Amplifier (RFPA). These devices provide the required speed, but suffer from very high power losses. To overcome this drawback, different solutions based on the use of fast-response DC/DC converters are presented in this paper. Several DC/DC converters, either to be used instead of an RFPA or to help an RFPA to achieve high efficiency, are thus analysed. The proposed HB-LED drivers enable the implementation of VLC transmitters without sacrificing one of the most important advantages of HB-LED lighting, namely its high power efficienc

    Exploring cosmic origins with CORE : The instrument

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    We describe a space-borne, multi-band, multi-beam polarimeter aiming at a precise and accurate measurement of the polarization of the Cosmic Microwave Background. The instrument is optimized to be compatible with the strict budget requirements of a medium size space mission within the Cosmic Vision Programme of the European Space Agency. The instrument has no moving parts, and uses arrays of diffraction-limited Kinetic Inductance Detectors to cover the frequency range from 60 GHz to 600 GHz in 19 wide bands, in the focal plane of a 1.2 m aperture telescope cooled at 40K, allowing for an accurate extraction of the CMB signal from polarized foreground emission. The projected CMB polarization survey sensitivity of this instrument, after foregrounds removal, is 1.7 mu K.arcmin. The design is robust enough to allow, if needed, a downscoped version of the instrument covering the 100 GHz to 600 GHz range with a 0.8 m aperture telescope cooled at 85K, with a projected CMB polarization survey sensitivity of 3.2 mu K.arcmin.Peer reviewe

    Exploring Cosmic Origins with CORE: The Instrument

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    We describe a space-borne, multi-band, multi-beam polarimeter aiming at aprecise and accurate measurement of the polarization of the Cosmic MicrowaveBackground. The instrument is optimized to be compatible with the strict budgetrequirements of a medium-size space mission within the Cosmic Vision Programmeof the European Space Agency. The instrument has no moving parts, and usesarrays of diffraction-limited Kinetic Inductance Detectors to cover thefrequency range from 60 GHz to 600 GHz in 19 wide bands, in the focal plane ofa 1.2 m aperture telescope cooled at 40 K, allowing for an accurate extractionof the CMB signal from polarized foreground emission. The projected CMBpolarization survey sensitivity of this instrument, after foregrounds removal,is 1.7 {\mu}Kâ‹…\cdotarcmin. The design is robust enough to allow, if needed, adownscoped version of the instrument covering the 100 GHz to 600 GHz range witha 0.8 m aperture telescope cooled at 85 K, with a projected CMB polarizationsurvey sensitivity of 3.2 {\mu}Kâ‹…\cdotarcmin

    Exploring Cosmic Origins with CORE:the instrument

    Get PDF

    Exploring cosmic origins with CORE: the instrument

    Get PDF
    We describe a space-borne, multi-band, multi-beam polarimeter aiming at a precise and accurate measurement of the polarization of the Cosmic Microwave Background. The instrument is optimized to be compatible with the strict budget requirements of a medium-size space mission within the Cosmic Vision Programme of the European Space Agency. The instrument has no moving parts, and uses arrays of diffraction-limited Kinetic Inductance Detectors to cover the frequency range from 60 GHz to 600 GHz in 19 wide bands, in the focal plane of a 1.2 m aperture telescope cooled at 40 K, allowing for an accurate extraction of the CMB signal from polarized foreground emission. The projected CMB polarization survey sensitivity of this instrument, after foregrounds removal, is 1.7 {\mu}Kâ‹…arcmin. The design is robust enough to allow, if needed, a downscoped version of the instrument covering the 100 GHz to 600 GHz range with a 0.8 m aperture telescope cooled at 85 K, with a projected CMB polarization survey sensitivity of 3.2 {\mu}Kâ‹…arcmin
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